Thoracic aortic aneurysm
Thoracic aortic aneurysm is the dilation (widening or bulging) of the aorta in the thorax (chest).
It doesn't usually cause any symptoms, but if the aneurysm widens rapidly it may cause severe chest pain. If it bursts (ruptures) it can be fatal.
- About aortic aneurysm
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About aortic aneurysm
What is the aorta?
The aorta is the largest artery in your body. It carries all the blood that is pumped out of your heart and takes it to the rest of your body.
The aorta projects upwards from the heart and then arches downwards, travelling through your chest (the thoracic aorta) and into your abdomen (the abdominal aorta).
The diameter of a healthy aorta is about 2 to 3 cm (about 1 inch).
What is a thoracic aortic aneurysm?
A thoracic aortic aneurysm is a weakened section of the thoracic aorta that bulges outwards. It can occur in the aorta as it leaves the heart and ascends into the arch (ascending aorta), within the aortic arch itself or in the aorta as it runs down from the aortic arch behind the heart towards the abdomen (descending aorta).
Aneurysms can also occur in the aorta as it goes through the abdomen (abdominal aortic aneurysms).
Thoracic aortic aneurysms often don't have any symptoms. However, if they start to compress the surrounding tissue in the chest, they can cause:
- chest pain
- shortness of breath
- difficulty swallowing
If the aneurysm widens rapidly, it can cause severe chest pain that spreads into the upper back. These symptoms aren't always due to thoracic aortic aneurysms but if you have them, you should visit your GP.
Aneurysms that occur in the ascending aorta near the heart may prevent the valve between the heart and aorta closing properly. This may cause blood to flow back into the heart. This is called aortic regurgitation. It can stop the heart pumping effectively (heart failure).
Rarely, the wall of the aorta tears and the layers that make it up separate as blood flows into it. This causes sudden and excruciating chest and back pain.
If the aneurysm ruptures it causes severe internal bleeding and can be fatal unless emergency surgery is carried out to repair it. The risk of an aneurysm rupturing increases as it gets wider.
There are several different causes of thoracic aortic aneurysms.
Atherosclerosis is the process of fatty deposits building up on the inside of arteries. It is thought to be one of the main causes of thoracic aortic aneurysm.
Certain things make you more likely to develop atherosclerosis. For example:
- being male
- increasing age
- having high blood pressure
- being obese
- being physically inactive
- eating a poor diet
Marfan's syndrome and Ehlers-Danlos syndrome
These are rare hereditary disorders that affect connective tissue - the framework of tissue that supports and holds the body together. They are common causes of aneurysms in the ascending aorta.
This sexually transmitted infection can lead to aortic regurgitation and aortic aneurysm in its late stages if it isn't treated. This might happen about 20 years after a person is first infected.
Tuberculosis (TB) can sometimes lead to thoracic aortic aneurysms if it isn't treated.
If your GP thinks you have an aortic aneurysm he or she will refer you to a cardiologist (a doctor who specialises in identifying and treating heart and blood vessel conditions). You may have several tests. Some examples are listed below.
- Chest X-ray. This may show a widening in your aorta.
- Transthoracic echocardiography. An ultrasound probe is run over your chest so that the heart's chambers and valves can be seen working.
- Transoesophageal echocardiography. A small ultrasound probe is passed into your oesophagus (gullet) after you have taken a light sedative to relax you. This allows a better image to be made of the descending thoracic aorta.
- Computed tomography (CT) scan. A CT scan uses X-rays to make a three-dimensional image of the chest. This can be used to identify or assess aortic aneurysms.
- Magnetic resonance imaging (MRI) scan. An MRI scan uses magnets and radiowaves to produce images of the chest. It can be used to identify or assess aortic aneurysms.
- Contrast aortography. A special dye is injected into the blood stream. The dye shows up the aorta and any aneurysms on an X-ray image.
At present there is no national screening programme to detect aortic aneurysms. However, ultrasound scans to screen for the condition are available from private clinics and hospitals.
If your aortic aneurysm has a diameter of about 5.5cm, or more then your doctor will probably recommend surgery to repair it. If you have an aneurysm with a smaller diameter, he or she may monitor it over time to see if it grows before deciding whether surgery is needed.
Any aneurysm causing symptoms will be treated with surgery. There are two main treatment options for an aortic aneurysm.
This is the traditional method of treating aneurysms. It's a major operation in which your surgeon opens your chest in order to access the aorta. He or she will then open the aorta and insert a graft. The graft is taken from another blood vessel in the body, or a synthetic graft may be used. The blood flows through the graft inside the aorta instead of going through the aneurysm and putting pressure on the wall of the aorta.
Endovascular stent graft replacement
Sometimes aneurysms can be treated without open surgery. A stent - a tube that is covered with synthetic graft material - is fed through the femoral arteries in your groin up though the aorta to the area of the aneurysm. Your surgeon uses X-ray images to guide the placement of the stent. The graft material bonds with the arterial wall and the blood flows through the stent instead of the weakened aneurysm.
This procedure is sometimes called endovascular aneurysm repair (EVAR). However, stents aren't suitable for everyone - it depends on the location of the aneurysm and other factors. To find out if EVAR is suitable for you ask your doctor about it.
There are some things you can do to reduce your chance of developing atherosclerosis and therefore an aneurysm, such as:
- not smoking
- having your blood pressure checked regularly
- exercising regularly
- maintaining a healthy weight
- eating a healthy diet
British Heart Foundation
- Kumar P and Clark M, Clinical medicine. 6th ed. London: Elsevier Saunders, 2005. 868
- Berne RM, Levy MN. Physiology. Mosby. 4 ed. 1998. 326
- Kasper D, Braunwald E, Fauci AS, et al,. Harrison's Principles of Internal Medicine. 16 edition. McGraw-Hill. 16 edition. 2005. p. 1481-1482
- Longmore M, Wilkinson I, Torok E. Oxford Handbook of Clinical Medicine. Oxford: Oxford University Press, 2001:480.
- French P. Syphilis. BMJ 2007;334:143-147. www.bmj.com
- Simon C, Everitt H, and Kendrick T, Oxford handbook of general practice. 2nd ed. Oxford: Oxford University Press, 2005: 315
- Jones L, Ayiku L, Wilson R. A systematic review of the recent evidence for the efficacy and safety relating to the use of endovascular stent-graft (ESG) placement in the treatment of thoracic aortic disease. Review body for interventional procedures. National Institute for Health and Clinical Excellence. February 2005. www.nice.org.uk
- Endovascular stent-graft placement in thoracic aortic aneurysms and dissections. National Institute for Health and Clinical Excellence. June 2005. www.nice.org.uk
- What is the genetic risk factor for thoracic aortic aneurysm. Does the NHS recommend screening for close family members of patients who have been diagnosed with the above in the absence of Marfan's Syndrome. National Library of health. Primary care question answering service. www.clinicalanswers.nhs.uk, accessed 12 November 2007
Abdominal aortic aneurysm
Coronary heart disease